With the development of modern electronic technology, components for achieving functions such as capacitive touch functions are disposed on a display panel device to bring convenience to users.
Nowadays, depending on the implementation, the capacitive touch function may be implemented as a self-capacitive touch function or a mutual-capacitive touch function. The self-capacitive touch function refers to a touch function achieved by capacitance formed between a touch electrode and ground, and the mutual-capacitive touch function refers to a touch function achieved by capacitance formed between a touch driving electrode and a touch sensing electrode.
In the related art, to achieve the capacitive touch function, typically a common electrode disposed on an array substrate is also used as a touch electrode, i.e., the common electrode is configured to receive a common voltage signal in the display state, and is used as a touch electrode to receive a touch driving signal in the touch state. When the touch electrode is used as a touch driving electrode, the touch sensing electrode corresponding to the touch driving electrode is disposed on a side of a color filter substrate facing away from the array substrate.
FIG. 1 is a schematic diagram of a structure of an array substrate in the related art. As shown in FIG. 1, the array substrate, on which the common electrode is also used as a touch electrode, includes: a transparent substrate 11; an interlayer 12 on the transparent substrate 11; and a Thin-Film Transistor (TFT) 13 on the interlayer 12, where the TFT 13 includes a source electrode 131, a drain electrode 132, a gate electrode 133 and a polycrystalline silicon layer 134, the gate electrode 133 is electrically insulated from the polycrystalline silicon layer 134 by a first passivation layer 141, the gate electrode 133 is electrically insulated from the source electrode 131 and the drain electrode 132 by a second passivation layer 142, and the source electrode 131 is electrically connected with a data line 135 via a first metal 136; the array substrate further includes an organic film layer 15 on the second passivation layer 142, a common electrode 16 on the organic film layer 15, and a pixel electrode 17 above the common electrode 16; where the common electrode 16 is electrically insulated from the pixel electrode 17 by a third passivation layer 143, and the common electrode 16 is also used as the touch electrode.
Based on operating principles of the capacitive touch function, the touch electrode needs to be charged at the beginning of the touch state (regardless of whether it is a self-capacitive touch function or a mutual-capacitive touch function), that is, a touch driving signal is provided to the touch electrode. As shown in FIG. 1, the common electrode 16 has a planar shape and is made of a transparent conductive material, thus the resistance of the common electrode 16 is large. Moreover, the overlapping area between the source electrode 131 of the TFT 13 as well as the first metal 136 and the common electrode 16 is large, so that a large load capacitance is formed, and hence, the product of the load capacitance and resistance of the touch electrode is large, resulting in a long charging time of the touch driving signal, so that there is insufficient time available for the touch state and the display state to operate in a time division manner.